1. Field of the Invention
This invention relates to video tape recorders (VTRs). More particularly, but not exclusively, the invention relates to rotary transducer head arrangements in a digital VTR.
2. Description of the Prior Art
Whereas in an analog VTR audio signals are generally recorded in longitudinally extending tracks, it is generally proposed that in digital VTRs the audio signals should be recorded in the oblique tracks in which the video signal is recorded. While this arrangement presents no serious difficulties in recording or in normally reproducing audio signals, there are some problems in editing the audio signals.
Thus the facilities required in audio editing are generally as follows:
(1) Each audio channel should be capable of being independently edited.
(2) Confidence playback of all recorded material including editing transitions should be possible.
(3) It should be possible to do cross-fade edits in a similar manner to analog VTRs, that is to say over a period of some 30 to 40 milliseconds. Preferably the cross-fade rates and periods should be variable.
(4) It should be possible to do track to track dubbing without lipsync problems.
(5) Confidence playback should be availabe when insert editing.
(6) Confidence playback should be available when assemble editing.
There are also, however, some mechanical and electrical constraints that need to be considered. For example, it is preferable that the number of head assemblies on the rotary head drum and the number of associated rotary transformers should not be too large, and it is preferable that the head assemblies be positioned to minimize cross-talk.